The present invention pertains particularly to wellhead connectors although it may be applied to other types of apparatus in which two tubular bodies are coaxially connected by radially extendable means carried by one of the bodies. A typical wellhead connector includes a generally tubular main body movably mounting a set of latch dogs for radial extension and retraction. The latch dogs, when extended, engage mating formations on the wellhead so as to prevent upward movement of the connector from the wellhead. In some connectors radial movement of the dogs is rectilinear, while in others, it is pivotal.
In a recent improvement in wellhead connectors, the main body also movably mounts support means, such as a split ring or a second set of circumferentially spaced members, for radial extension and retraction at least partially independently of the latch dogs. In operation, the latch dogs and support means are successively radially extended. The latch dogs are moved to their extended positions without the transmission of any substantial longitudinal force to the wellhead. Thus the relatively hard latch dogs do not "plow" or gouge into the necessarily soft metal of the wellhead. The support means are then extended to wedge between the latch dogs and the main body. This tightens the connection longitudinally. However, since there is no direct contact between the support means and the wellhead, the latter is still protected from deformation.
In such improved connector, a release means is needed not only to initially break the tight wedging fit of the support means between the latch dogs and main body, but also to completely retract the support means. Since the support means are preferably linked to the latch means, the latter can thereby be indirectly retracted.